dmaengine: mediatek: do not issue a new desc if one is still current

[ Upstream commit 2537b40b0a4f61d2c83900744fe89b09076be9c6 ]

Avoid issuing a new desc if one is still being processed as this can
lead to some desc never being marked as completed.

Signed-off-by: Guillaume Ranquet <granquet@baylibre.com>
Link: https://lore.kernel.org/r/20210513192642.29446-3-granquet@baylibre.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/dma/mediatek/mtk-uart-apdma.c b/drivers/dma/mediatek/mtk-uart-apdma.c
index 311d7c236d27bb0bba647affeeba8143368ae07a..e420e9f72b3dd665065868e0ea128f8a22de6d34 100644 (file)
--- a/drivers/dma/mediatek/mtk-uart-apdma.c
+++ b/drivers/dma/mediatek/mtk-uart-apdma.c
@@ -204,14 +204,9 @@ static void mtk_uart_apdma_start_rx(struct mtk_chan *c)
 
 static void mtk_uart_apdma_tx_handler(struct mtk_chan *c)
 {
-       struct mtk_uart_apdma_desc *d = c->desc;
-
        mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_TX_INT_CLR_B);
        mtk_uart_apdma_write(c, VFF_INT_EN, VFF_INT_EN_CLR_B);
        mtk_uart_apdma_write(c, VFF_EN, VFF_EN_CLR_B);
-
-       list_del(&d->vd.node);
-       vchan_cookie_complete(&d->vd);
 }
 
 static void mtk_uart_apdma_rx_handler(struct mtk_chan *c)
@@ -242,9 +237,17 @@ static void mtk_uart_apdma_rx_handler(struct mtk_chan *c)
 
        c->rx_status = d->avail_len - cnt;
        mtk_uart_apdma_write(c, VFF_RPT, wg);
+}
 
-       list_del(&d->vd.node);
-       vchan_cookie_complete(&d->vd);
+static void mtk_uart_apdma_chan_complete_handler(struct mtk_chan *c)
+{
+       struct mtk_uart_apdma_desc *d = c->desc;
+
+       if (d) {
+               list_del(&d->vd.node);
+               vchan_cookie_complete(&d->vd);
+               c->desc = NULL;
+       }
 }
 
 static irqreturn_t mtk_uart_apdma_irq_handler(int irq, void *dev_id)
@@ -258,6 +261,7 @@ static irqreturn_t mtk_uart_apdma_irq_handler(int irq, void *dev_id)
                mtk_uart_apdma_rx_handler(c);
        else if (c->dir == DMA_MEM_TO_DEV)
                mtk_uart_apdma_tx_handler(c);
+       mtk_uart_apdma_chan_complete_handler(c);
        spin_unlock_irqrestore(&c->vc.lock, flags);
 
        return IRQ_HANDLED;
@@ -363,7 +367,7 @@ static void mtk_uart_apdma_issue_pending(struct dma_chan *chan)
        unsigned long flags;
 
        spin_lock_irqsave(&c->vc.lock, flags);
-       if (vchan_issue_pending(&c->vc)) {
+       if (vchan_issue_pending(&c->vc) && !c->desc) {
                vd = vchan_next_desc(&c->vc);
                c->desc = to_mtk_uart_apdma_desc(&vd->tx);